Industrial furnaces are well known in the art. A typical industrial furnace includes a furnace wall comprising an outer shell formed of steel and an inner protective refractory brick lining. Molten materials such as metal or aggressive chemicals are contained in industrial furnaces of this nature and therefore, integrity of the refractory brick linings is of primary concern. The refractory brick lining includes multiple layers of refractory brick with safety refractory brick being disposed between the outer shell and inner refractory brick that is in contact with the molten materials or aggressive chemicals.
Unfortunately, exposure of the refractory brick lining to molten materials or aggressive chemicals tends to deteriorate the refractory brick lining over time resulting in a loss of thickness. As the refractory brick lining deteriorates, molten materials or aggressive chemicals in the industrial furnace may penetrate the inner refractory brick thereby exposing safety refractory brick to the molten materials or aggressive chemicals. This creates discontinuities in the refractory brick lining which over time may result in exposure of the outer shell to molten materials or aggressive chemicals. If this occurs, the outer shell may be compromised placing individuals at risk. As a result, it is necessary to inspect industrial furnaces regularly to determine the condition of the refractory brick linings.
One prior art technique to inspect an industrial furnace makes use of thermal coupling devices in association with numerical modeling techniques to develop a model of the industrial furnace based on known heat transfer characteristics of the refractory material. Unfortunately, this technique suffers disadvantages in that the thermal coupling devices require high maintenance. Also, the model of the industrial furnace is often inaccurate yielding poor results.
Infrared thermographic imaging, ground penetrating radar and laser measurement have also been used to inspect industrial furnaces. Infrared thermographic imaging suffers disadvantages in that this imaging technique only permits imaging of the outer shell and is limited to imaging the first few centimetres of the outer shell. Ground penetrating radar suffers disadvantages in that it cannot be used to image metal surfaces and therefore, it must be used within the industrial furnace. This of course requires inspection to be performed only when the industrial furnace is not in operation. This is also the case for laser measurement which can only be applied to the inside of the furnace, when the furnace is not in operation, so that the laser can measure the loss of thickness from the surface of the inside layer of the refractory brick lining.
None of these above-described techniques permits subsurface deterioration of the overall integrity of the refractory brick layers, the ingress of molten metal between, or into, the individual refractory bricks, or between the layers of refractory brick, to be detected. As a result, limited success has been achieved using these techniques. As will be appreciated, improved techniques to inspect industrial furnaces are desired.
It is therefore an object of the present invention to provide a novel system and method for inspecting an industrial furnace or the like.